First fountain pen of my life. Parker Vector with "Medium" nib. I've already had it for two weeks, and although this was only meant to try out fountain pens, I think I'll keep it, since the nib is a great compromise between being smooth while not being fussy with office paper. Already chewed through a cartridge. Only bad thing with the pen is that the grip is a little meh – my fingers don't really like it.
My next will probably be a Lamy (mostly Safari). Any recommendations for the nib size so it fits my criteria?
Feedback (aka the scratchy friction from the nib rubbing across the paper fibers) all depends on both the paper and the type of nib you get.
The polished steel nib will have less feedback than the black steel nibs but the polished steel nibs will have greater variation in the line thickness.
Higher end/premium paper like Rhodia, Clairefontaine, Leuchtturm 1917 etc will feature smoother paper which will give less feedback.
Some feedback is wanted so you know how you are writing but how much feedback is needed is up to both the user and the situation.